The security chief of a Leicestershire prison has warned residents on the other side of the walls that inmates could use householders' wifi for criminal activities.

A letter sent to residents near HMP Gartree requested assistance in preventing detainees logging on to wireless signals on illegally-held phones.

The document, signed by the prison’s head of security, starts "Dear neighbour" and says that its writer "makes no apology for contacting you to ask for help and assistance".

“As part of a recent operation we identified that wifi signals from nearby properties are breaching the prison boundary meaning that potentially prisoners could log on through the public access element of your network," it continues.

“In theory prisoners could be using your network to commit criminal activities.”

The letter sent to the prison's neighbours

The letter added that this issue is exacerbated due to the prison’s isolated location.

It continued: “Being somewhat isolated we also suffer from contraband being thrown over the fences, to be collected by prisoners.

"Items including mobile phones and drugs in tennis balls and packages have been recovered.

“Several methods have been employed to get phones an illicit items into prison, including smuggling by visitors, throw overs of parcels and even delivery by drones.

“We use a mixture of both covert and overt tactics to identify and recover illegally-held devices as well other contraband items and work closely with the local police who have no hesitation in prosecuting offenders.”